Spotted wing drosophila alert 7/24/18

Hi Berry Growers,
Many spotted wing drosophila (SWD) adults have been caught in traps over the past week. Current weather conditions of high humidity and showers favor buildup of SWD. If you intend to spray your raspberries and/or blueberries for SWD, spray now, even though rain showers will wash off insecticides. Adding a sticker such as Nu Film P at 4-16 oz/100 gallons should improve efficacy. It may also be helpful to add 1-2 pounds of sugar/100 gal to stimulate SWD to feed on insecticides.

Raspberry fruit infested with SWD have been found in RI, but I have not found any SWD-infested blueberries yet. To look for larvae in your fruit do a quick salt test. Pick 100 raspberries or blueberries and place in large ziplock bag. Squish the berries and add 1 cup of water + 1 tablespoon table salt (dissolved in water). Larvae will soon rise to the surface. See this link for more detailed instructions and pictures:

Harvested fruit should be chilled as soon as possible to slow down development of SWD inside fruit.

See this link from Mary Concklin from UConn for registered insecticides for managing SWD in small fruit:
Be sure to check the Preharvest Interval and rotate between classes of insecticides (IRAC code).

Here’s a quick-check chart from David Handley from the University of Maine.


Trade Name Days to Harvest
Days of Residual
Assail® 1 5-7
Mustang Max® 1 7
Bifenture® 1 (3 raspberry) 7
Brigade® 1 (3 raspberry) 7
Danitol® 3 7
Delegate® 3 (1 raspberry) 7
Entrust® 3 (1 raspberry) 3-5
Exirel® 3 (not for raspberry) 5-7
Imidan® 3 (not for raspberry) 5-7


Contact me if you have questions,